Food manufacturers sometimes add calcium acetate to puddings and sweet sauces as a thickening agent. What volume of 0.500 mol/L calcium acetate, Ca(CH3COO)2 (aq), contains 0.300 mol of acetate ions?
So I've been over this a hundred times and I still can't get past the part where i find the moles of calcium acetate.
I can't do
Moles Ca(CH3COO)2= MASS x (1 mol/ 158.11)
158.11 is the molar mass of calcium acetate, by the way
I can't find the moles for calcium acetate, so then i can't do the net ionic equation and do the mole ratio... I'm just really confused about this question
I'm really sorry if I don't make sense, but I'd really appreciate your help
Follow up if need be.
You want 0.3 mol of Ac^-. That will be 1/2 that or 0.15 mol of Ca(Ac)2 since 1 mol Ca(Ac)2 contains 2 Ac^- ions.
Then M = mols/L
M = 0.5M
mols = 0.15
L = ?
Let me try to do this the way you started. Start with what you have and convert stepwise to end up with what you want.
0.3 mols Ac^- x (1 mol Ca(Ac)2/2 mol Ac^-) x (1 mol Ca(Ac)2/0.5 mol Ca(Ac)2/L)) = 0.300 L or 300 mL of the 0.5M solution of Ca(Ac)2.
Note mols Ac^- cancel with mols Ac^- to leave mols Ca(Ac)2 then mols Ca(Ac)2 cancel with mols Ca(Ac)2 to leave L. I prefer to do it in two steps. I think it's easier to follow that way.
mols Ca(Ac)2 = 1/2 mols Ac^- = 0.30/2 = 0.15.
Then L = mols M = 0.15/0.5 = 0.300 L or 300 mL.
Preparation of magnesium sulphate.
Magnesium sulphate (Epsom salt) is a soluble solid that is used as a mild laxative in causing movement of bowels in humans. Prepare a solution of magnesium sulphate. Obtained it as a solid. Use this information and answer the question.
1. Method
2. Balance equation
3. Net ionic equation
4. Observation
1. Method:
To prepare a solution of magnesium sulphate, we can dissolve the solid Epsom salt in water. Here are the steps:
- Weigh out the desired amount of Epsom salt (magnesium sulphate) using a balance.
- Add the Epsom salt to a volumetric flask containing some distilled water.
- Swirl the flask to dissolve the Epsom salt. If necessary, add more water to fill the flask to the mark.
- Stopper the flask, invert it a few times to mix the solution, and label the flask with its contents and concentration.
2. Balanced equation:
MgSO4 (s) + 2H2O(l) → MgSO4 · 2H2O (s)
3. Net ionic equation:
Mg2+(aq) + SO4 2-(aq) → MgSO4 (s)
4. Observation:
When Epsom salt is dissolved in water, the resulting solution is clear and colorless.
Preparation of magnesium hydroxide.
Magnesium hydroxide is a white insoluble solid that is used as an antacid to relieve upset stomach. Obtain it as solid. Use this information and answer the question.
1. Method
2. Balance equation
3. Net ionic equation
4. Observation
1. Method:
To obtain magnesium hydroxide as a solid, we can perform a precipitation reaction between a soluble magnesium salt and a strong base such as sodium hydroxide or potassium hydroxide. Here are the steps:
- Add a solution of a soluble magnesium salt (e.g. magnesium chloride or magnesium nitrate) to a solution of sodium hydroxide or potassium hydroxide while stirring.
- The magnesium ions will react with the hydroxide ions in the base to form insoluble magnesium hydroxide.
- Continue to stir the mixture until all the magnesium hydroxide has precipitated out.
- Collect the precipitate by filtration, wash it with water to remove any impurities, and dry it in an oven or air.
2. Balanced equation:
MgCl2 (aq) + 2NaOH (aq) → Mg(OH)2 (s) + 2NaCl (aq)
3. Net ionic equation:
Mg2+(aq) + 2OH-(aq) → Mg(OH)2(s)
4. Observation:
When magnesium chloride is added to sodium hydroxide, a white precipitate of magnesium hydroxide is formed. The precipitate can be collected by filtration, washed, and dried to obtain the solid magnesium hydroxide. It has a white, powdery appearance and is insoluble in water.
Preparation of calcium carbonate.
Calcium carbonate is a white insoluble solid occurring naturally as chalk, limestone, marble and calcite. It is useful building material. Devise a way of making some calcium carbonate from the substances provided. Obtain it as a powder. this information and answer the question.
1. Method
2. Balance equation
3. Net ionic equation
4. Observation
1. Method:
To make calcium carbonate, we can perform a precipitation reaction between a soluble calcium salt and a soluble carbonate salt. Here are the steps:
- Dissolve a soluble calcium salt (e.g. calcium chloride or calcium nitrate) in a beaker with distilled water.
- In a separate beaker, dissolve a soluble carbonate salt (e.g. sodium carbonate or potassium carbonate) in distilled water.
- Slowly add the carbonate solution to the calcium solution while stirring continuously.
- A white precipitate of calcium carbonate will form.
- Continue stirring until all the calcium carbonate has precipitated out.
- Collect the precipitate by filtration, wash it with water to remove any impurities, and dry it in an oven or air.
2. Balanced equation:
CaCl2 (aq) + Na2CO3 (aq) → CaCO3 (s) + 2NaCl (aq)
3. Net ionic equation:
Ca2+(aq) + CO3 2-(aq) → CaCO3 (s)
4. Observation:
When calcium chloride is mixed with sodium carbonate, a white precipitate of calcium carbonate is formed. The precipitate can be collected by filtration, washed, and dried to obtain the powder form of calcium carbonate. Calcium carbonate is a white, crystalline powder that is insoluble in water but dissolves in acid with effervescence.
No problem, I'm here to help! Let's break it down step by step to find the moles of calcium acetate.
First, let's write the balanced chemical equation for calcium acetate:
Ca(CH3COO)2(aq) -> Ca2+(aq) + 2CH3COO-(aq)
From the equation, we can see that 1 mole of calcium acetate produces 2 moles of acetate ions (CH3COO-). So, the mole ratio is 1:2.
Given that you have 0.300 mol of acetate ions, we can use the mole ratio to find the moles of calcium acetate required.
Moles of calcium acetate = 0.300 mol of acetate ions * (1 mole of calcium acetate / 2 moles of acetate ions)
The mole ratio of 1 mole of calcium acetate / 2 moles of acetate ions is derived from the balanced chemical equation.
Moles of calcium acetate = 0.300 mol / 2 = 0.150 mol
So the volume of 0.500 mol/L calcium acetate containing 0.300 mol of acetate ions is 0.150 mol.
To find the volume, we can use the equation:
Volume = Moles / Concentration
Volume = 0.150 mol / 0.500 mol/L = 0.300 L
Therefore, the volume of 0.500 mol/L calcium acetate needed is 0.300 L.
I hope this clears up the confusion and helps you find the answer to your question. Let me know if you have any further questions!